1. Field of the Invention
The present invention relates to a clamp for a cable duct that has, at its open side, in regions of free ends of its side walls, inward projecting strip-shaped edges with the clamp including a bridge section for bridging the open side of the cable duct, and connection portions provided at opposite longitudinal ends of the bridge section for engaging the strip-shaped edges.
2. Description of the Prior Art
Cable ducts mentioned above serve generally for receiving electrical cables and conductors. They can be mounted in indentations formed in walls, ceilings, or floors. Often, they are mounted on outer surfaces of walls. Often used cable ducts have a substantially U-shaped cross-section and have a bottom wall from which two side walls extend primarily at an approximately right angle. A side of the cable duct opposite the bottom wall remains open to provide for insertion of cables. Also known are so-called angular ducts which are formed for mounting in a corner formed by two butt-joined walls. The angular ducts have essentially a triangular cross-section which is formed of a bottom wall and two side walls projecting from the bottom wall and forming an obtuse angle or is formed of two side walls connected with each other along their longitudinal sides.
Conventional cable ducts are closed with covers after cables have been placed into the ducts. The covers lockingly engage in undercuts formed in outer sides of the side walls at their free ends. The inserted cable loads the side walls pushing them outwardly. This can cause difficulties during mounting and securing of the cover. To provide for a greater stability of the side walls, which are loaded by inserted cables, there are provided clamps which bridge the open side of the cable duct and are secured on strip-shaped edges which project inward from inner surfaces of the side walls in the regions of the free ends of the side walls and which extend in a longitudinal direction of the cable duct. German Utility Model DE-U-79 31 274 discloses a clamp for a cable duct which is secured in elongate slots formed in the strip-shaped edges of the side walls. To this end, the clamp has, at its opposite longitudinal ends, respectively, two locking fingers with hooks, which are separated by a slot. The locking fingers are pressed together by a force acting transverse to the longitudinal extent of the clamp. Thereby, the width of the clamp, in the region of the hooks, is reduced, and the locking fingers can be inserted in the slot. A locking member inserted into the slot between the locking fingers, which can be removed, if necessary, prevents an accidental disengagement of the clamp from the edges of the side walls.
The clamp described above can only be secured in slots provided in respective edges and which are spaced by a predetermined distance. Mounting of the clamp in any arbitrary location of the cable duct, e.g., in the region of a duct or cover junction, is not possible. The release of the mounted clamp, e.g., for insertion of another cable, is very cumbersome. In order to press the locking finger toward each other, first, the locking member need be removed from the slot between the two fingers. To effect this, the use of both hands is necessary and, sometimes, the use of an auxiliary tool, e.g., a screwdriver or the like is required for removing the locking member.
German Utility Model DE-U-295 15 365 discloses a clamp having, at its longitudinal ends, somewhat U-shaped clamping sections. The strip-shaped edges, which project inward from the free ends of the side walls, are provided with longitudinal flutes at least on their upper surfaces. Together with correspondingly formed inner surfaces of the clamping sections of the clamp, they form a fluted locking connection. The advantage of this clamp consists in that it can be longitudinally displaced, if necessary, and can be mounted at any arbitrary location on the wall edges of the cable duct. The mounting of the clamp is rather easy. However, the clamp dismounting, e.g., in order to insert a new cable, requires the use of both hands for releasing the fluted connection.
Accordingly, an object of the present invention is a clamp for a cable duct which can be easily mounted at any arbitrary location along the cable duct. Another object of the present invention is a clamp for a cable duct which, after being mounted, can be easily displaced to a desired position, if needed. A further object of the invention is a clamp for a cable duct which will prevent a cable inserted into the duct from falling out. A still further object of the present invention is a clamp for a cable duct which will insure that it could not be accidentally released, in particular, with the closed cover. A yet further object of the present invention is a clamp for a cable duct which can be released with one hand, at least at one of its side, for insertion of another cable. Also, an object of the present invention is a clamp for a cable duct which will insure an adequate stiffness of the side walls so that the cover can be mounted with an adequate clamping force.